Potential effect of SLp on the sensitivity of Lactiplantibacillus plantarum strains to Penicillin-G.

AIM: This study aimed to investigate how the presence and absence of S-Layer proteins (SLp) affects bacterial sensitivity to Penicillin-G. METHODS: The phenotypic feature of strains in the presence and absence of SLp was evaluated using disk diffusion and nitrocefin tests. The β-lactam resistance gene (blaZ) was detected by Polymerase chain reaction (PCR). Viable cell counts were performed at 0, 4, 8, and 12 hours in Penicillin-G-supplemented medium for strains with and without SLp. Pearson's correlation coefficient was used to analyze the relationship between exposure time and viability. RESULTS: In the absence of SLp, an increase in the zone diameter of all strains has been observed. In the viability test, Lpb. plantarum DA225 had an initial viability of 8.47 log CFU/mL. After 12 hours without SLp, it lost 4.97, finishing with 3.50 log CFU/mL. Pearson's correlation showed a positive correlation of 0.68 between the 4th and 12th hours, and 0.97 between the 8th and 12th hours. CONCLUSIONS: Suggesting results SLp deficiency does not completely affect the survival of the bacterium, it causes it to become physiologically weaker, and that the SLp has an indirect but significant effect on cell viability.